Compression member



A ril 20, 1948. w. s. MITCHELL COMPRESSION MEMBER Filed Jan. 31, 1945 ZN m INVENTOR MUM 6'. MIC/I511.

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' Patented Apr. 20, 1948 COMPRESSION MEMBER Walter G. Mitchell, Aurora, 111., assignor to Independent Pneumatic Tool' Company, Ill., a corporation of Delaware Chicago;

Application January 31, 1945, Serial No. 575,426

This invention relates to improvements in compression members of the type comprised of resilient rubber or equivalent material for absorbing shocks and stresses in fabricated structures.

In particular, the invention concerns compression members of the character shown and claimed in my copending application Serial No. 564,338, filed November 20, 1944, the specific form of compression member disclosed in this present application being a modified-form of the invention defined in said copending application.

In the foregoing respect, my invention in its disclosure in the instant application consists in providing a compression member of resilient rubber or equivalent material and in which axially disposed, spaced columns of such material resist through the member to maintain it relatively,

6 Claims. (Cl. 279- 1911) cool in operation in performing its cushioning function under load.

A further object of my invention is to have an appreciable portion of the axial dimension of the member occupied by the columns to provide in total a relatively large air space within the member between the columns for an effective cooling action as the member is compressed and expanded in operation from repeated shocks or blows on the member as when used as a bumper member in a chisel retainer for a portable power operated hammer or other percussive tool.

A further object of my invention in respect to the instant disclosure is to provide'the compression member with means interconnecting the columns to brace them against compressive or other forces applied on the member to stabilize the member as a manufactured article.

A further object of my invention is to provide said stabilizing means in the form of ribs or webs extending between and connected with the columns and constituting in conjunction therewith baflies to give turbulence to the air circulating through the member to enhance its cooling effect and thereby enable a resilient rubber material to be employed as the composition for the compression member without early failure thereof from the internal heat produced within the body of the member in its rapid and repeated flexing. A further object of my invention consists in The invention consists further in the combination and the structural features hereinafter described and claimed.

In'the accompanying drawings- Fig. 1 shows the compression member above defined in a chisel retainer of a pneumatic hammer, the retainer and the adjacent portion of the tool being shown in longitudinal section;

Fig; 2 is a cross-sectional viewtaken on line 22 of Fig. 1, the upper flange element of the retainer structure bearing on the adjacent compression member being broken away for the purpose of illustration;

j Fig. 3 is a fragmentary view in longitudinal sectionoi the parts shownin Fig. 1, the compression members being shown compressed by the mounting sleeve for the chisel Fig. 4 is a top plan' viewof the compression member removed irom'the retainer and partly in section to show the column and web arrangement of the construction;

F1Fig. 5 is a sectionalview taken on line 5-5 of g.4; r Fig. 6 is a fragmentary view partially in section of a modified form of my invention to be later described; and

1 Fig. 7 is a sectional view taken on line 'l1 of Fig. 6 toshow details of said'modified form.

- As shown in the drawings, the compression -*member I of my invention comprises a body portion 2 made of solid resilient rubber or equivalent materlaland' of the size and shape required for the compression'member to serve as a'shock or jar absorber in a fabricated structure. For a chisel retainer for a portable pneumatic chipping hammer or other percussivetool, the compression memberlis molded fromthe desired resilient material into annular form to fit about the mounting sleeve "3 of the retainer and be located in the space betweenthe mounting sleeve 3 and the outer sleeve 4 of the retainer device as depicted inFigil. I

J In accordance with my inventionthe compression member I in being molded or otherwise fashioned isprovidedwith upper. and lower wall sections 5, G,"at the *opposite end's of the member the drawings, the upper wall. section 5 seats the combination of the herein defined compression-member in the fabricated structure in which one or more of said members are employed, as for example the chisel retainer combination above noted.

" and which wall sections form the seating surfaces iorthe member in use.' -As will benoted from against the overhanging flange I at the upper or inner end of the mounting sleeve 3, while the lower wall sectionli seats against either the introverted flange s at theouterendoi the retainer sleevejlor against theadjacent lower compresto sion member i when-two or' more of them are used L 2,440,150 3 4 t l in the superimposed arrangement shown in Figs. member and these motions provide for the intake 1 and 2. and ejection of air with respect to the spaces The flange 8 forms a stop for the compression between the columns and the wall sections to member assembly and supports the latter for create a circulation of air through the member compression in response to blows of the chisel 9 5 for cooling the same. The movement of the parts when struck by the hammering piston II) in its under the inherent resiliency of the rubber matereciprocation in theh p rial to. expandpyhen released draws air into the This Qccfurswhen hep iston Ill e vspaces between the cohininsandthe.wall'sections, the chisel 9 is out of contact with the work or while a reverse movement fif'the parts under a when the chisel glances ofi the work in a toolm compressive force ejects the air producing the operation. It is to be understood that the piston air circulation or air flow just mentioned. The ID is compressed air operated as in tool's'of the air fiowk'eps the compression member relatively character shown. ,cooli the rapidand repeated flexings when in The blows of the chisel I I longsthe life and effectiveness of compression members I when cli'i's'el'i I members, especially when made jected sufliciently through the rnquntingsleeve 3 ie'ntrubb'r material.

to bring the inset summers-13ertne cnisel 'rhe' alr circulation created by the novel conagainst the upper end of the mountin g sleeveit 1 struction of the member I carries off the internal a shown in Fig. 3. When this occurs the mountheat 'pro't'luced therein by friction and enables in ske r h e-si t t ath cit-the shoulders, 20 r g q eaa nwarjdiyfpr y ndpt" pression inembers I "are comp *opetane ofitaememaer as a r der the ueue "conditions, PI

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@meu ts ri 9 la h. re 1 of the barrel I2. The inner anlssh st e iewarslly ta e Ei ;Th' nneierredi t yv tnmvid-" ;,if e ve? .eo ectionisbx m ldinei Qmnre jibtherthn I esi n' memben as .hereinbefore.i d ated. The 09 bore of the l8 extend maxial yisofrthe .mem fi l I ;.-th i;d-.irect1 n.;o the; appliedwcompressi e r 1. i, band; m y; e? medalist:tsubstantiallyethezsamesdi ameter, but not necessarily so. The columns;;l8 are: grouped ,-0I arran ed-z abbut::theeximpf'ith rnemb enin spac.e ;-'1:e.1ation;;both circumferentially i ternal spaces l within'athe membergfpr the.. i qlll iion pof iair; i-therethrougha: for 'anaintaining the member'relativelya cool -in;,work .tthatris,= in fleggin in .i-the application":and-the*release I of V a load t t .1 nix- J .l. as it Us The resilie t .0 .m l .tion;:inv;.rle p91!ei t9: a

and 7 are made larger in diameter than the columns in the previous figures and, hence, are disposed in closer relation between the lateral edges of the compression member. In the showing in Fig. 6, the columns 22 almost touch tangentially. This increase in column size gives the compression member greater stability and resistance. To facilitate the flow of cooling air between the columns 22, I provide one or more of them with lateral air flow passages 24, 24, one in each column and oppositely disposed so that the combined dimension of each two registering passages 24 allows for a relatively large flow of air. As shown in Fig. 7, each column 22 which is provided with the passages 24 has the latter arranged adjacent to the upper and the lower wall sections 5a, 6a,

respectively. For air flow purposes, one or more of the columns 22 is each provided with a port opening 25 connecting its bore 23 with the outside of the compression member as shown in Fig. 7.

The spacing between the columns 22 gives the internal structure of the device a cellular effect for the ingress and egress of air for coolin purpose, but by the closer spacing shown in Fig. 6 the passages 24 provided in the sides surfaces of the columns facilitates this air flow.

The details of construction and arrangement of parts shown and described may be variously changed and modified without departing from the spirit and scope of my invention, except as pointed out in the annexed claims.

I claim as my invention:

1. A compression member of the character described comprising, a body member made of a resilient rubber-like material and having upper and lower end wall sections and a complement of columns integrally connected with and extending continuously between said end wallsections, said columns being disposed between the lateral edges of the member and disposed in spaced relation to provide spaces within the member for the ingress and egress of air to cool the member in flexing in response to a compressive force thereon, and a web formation between and interconnected with the columns and the adjacent end wall sections to brace the same, the webs at one end of the compression member extending generally towards the webs at the opposite end of the compression member and terminating short of each other to provide baffles and an opening therebetween for the passage of cooling air.

2. A compression member of the character described comprising, a body member made of a resilient rubber-like material and having upper and lower wall sections and a complement of columns therebetween, said columns being disposed between the lateral edges of the member and disposed in spaced relation to provide spaces Within the member for the ingress and egress of air to cool the member in flexing in response to a compressive force thereon, and a web formation between and interconnectedwith the columns to brace the same, said webs being disposed at the opposite ends of the columns where joined to said upper and lower wall sections.

3. A compression member of the character described comprising, a body member of resilient material and formed to provide upper and lower end wall sections with a complement of columns integrally connected with and extending continuously between said upper and lower end wall sections to resist a compressive force applied on the member in the direction in which the columns extend, one or more of said columns being made hollow to provide a bore for the passage of air therethrough and said bores opening through at least one of said end wall sections.

4. A compression member of the character described comprising, a body member of resilient material and formed to provide upper and lower end wall sections with a complement of columns integrally connected with said upper and lower end wall sections and extending continuously therebetween to resist a compressive force applied on the member in the direction in which the columns extend, one or more of said columns being made hollow to provide a bore .for the passage of air therethrcugh, certain of said hollow columns each having a definite port intermediate its ends connecting the bore with the exterior of the member.

5. The combination with the barrel of a percussive tool having a power operated hammering piston reciproc-able therein, of a chisel with shoulders insertible into the barrel to receive the blows of the piston, a retainer device for the chisel having an outer sleeve secured to the barrel and an inner or mounting sleeve for the chisel in the path of said shoulders, said outer sleeve having an inwardly extending flange at its outer end and said inner sleeve having an outwardly extending flange at its inner end,'and resilient bumper means supported between said flanges about the mounting sleeve for absorbing the impacts of the shoulders on the mounting sleeve when struck thereby, said bumper means being comprised of a plurality of superimposed compression members, each having axially spaced upper and lower end wall sections at the opposite ends of the compression member and a complement of axially extending columns between and integrally connected with said end wall sections for holding the columns and the end wall sections in fixed relation, the columns of each compression member being spaced apart between the outer peripheries of the compression member for the flow of air therethrough to cool the same, the compression members at the ends of the bumper means having their outermost end wall sections in contact with the flanges of the respective sleeve members, and their other end wall sections in contact with each other.

6. The combination as defined in claim 5 characterized by the fact that each compression member has webs interconnected with the columns and its end wall sections and extending axially of the compression member to brace the same,

WALTER G. MI'ICHELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 132,765 King Nov. 5, 1872 1,108,488 Bugg Aug. 25, 1914 1,882,520 Pollard May 19, 1930 1,994,234 Shreover May 27, 1930 2,395,949 Wilkins Mar. 5, 1946 FOREIGN PATENTS Number Country Date l40,465 Great Britain June 20, 1921 

